1. Field of the Invention
The present invention relates to an electronic card unit and a method for removing heat generated from electronic components. In preferred embodiments, the card unit has a heat-radiating structure which can efficiently remove heat generated from electronic components in the electronic card unit.
2. Description of Related Art
Electronic components such as highly integrated semiconductor devices produce heat when the components are activated. Heat removal is essential for an electronic card unit which consists of such electronic component mounted on a printed circuit board. In particular, in electronic communication equipment having a plurality of card units in its card slots, a large amount of heat is generated. Efficient heat removal poses a serious technical problem. For this reason, various techniques have been proposed.
In a heat radiating structure disclosed in Japanese Unexamined Patent Publication No. Sho 63(1988)-152200, a component as a source of heat on a printed circuit board is connected to heat-cooling fins via a pipe, and the fins are further connected to movable heat-cooling fins that protrude into an air chamber, whereby heat is efficiently removed.
In a heat-radiating structure disclosed in Japanese Unexamined Patent Publication No. Hei 10(1998)-270884 (Patent Document 2), a pipe on the side of component connected to a heat-generating element on a printed circuit board is removably connected to another pipe connected to a heat-radiating plate placed on the top surface of communication equipment, thereby removing heat of the heat-generating element from the external heat-radiating plate through the connected heat pipes.
In general, a number of card-like electronic units are accurately inserted into an electronic communication equipment frame, and as described above, heat must be efficiently removed. Therefore, printed circuit boards of electrical modules are required to be robust and accurate. Furthermore, the space for removing heat must be compactly allocated.
The heat-radiating structure described in Japanese Unexamined Patent Publication No. Sho 63(1988)-152200 (the third to 15th lines in the lower right section of P. 1, FIG. 1) has fixed heat-radiating fins and movable heat-radiating fins. Thus, it is difficult to produce a robust and accurate cooling system. In addition, the fin construction prevents the system from being compact.
Heat-radiating space in the equipment must be provided, such that the heat-radiating structure described in Patent Document of Japanese Unexamined Patent Publication No. Hei 10(1998)-270884 (paragraphs 0011 to 0013, FIG. 1) conducts heat from the heat-generating element through the heat pipes to the external heat-radiating plate. Therefore, it is difficult to compactly design the heat-radiating structure.